> For the complete documentation index, see [llms.txt](https://docs.hyperdbg.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hyperdbg.org/using-hyperdbg/prerequisites.md).

# Prerequisites

In HyperDbg, there is a fundamental term called "**event**". Each time you use HyperDbg, you set a special event; for instance, imagine you want to intercept system-calls. You should set up an event that will be triggered in the case of a syscall execution, or when you set a hidden hook event on a particular function.

Whenever these events are triggered, HyperDbg performs specific actions that are configured by you.

#### What are HyperDbg's actions?

HyperDbg has three types of actions. These actions are **Break**, **Script**, **Custom Codes**.

**Break** is exactly like classic-debuggers, where all of the cores are paused and won't run any instruction without the debugger's permission. (This feature is not available in local debugging).

**Script** is a feature that helps you view the parameters, registers, and memory without breaking into the debugger and running your custom script. You can use it when you want to analyze your target, and it creates the logs or run codes in the kernel.

It's much faster than exiting to the debugger and continues from there as all of these logging mechanisms are done in the kernel, and you see the messages in user-mode.

**Custom Codes** gives you the ability to run your custom assembly codes whenever a special event is triggered; this option is fast and powerful as you can customize the HyperDbg based on your needs.

#### What are the conditions?

Each event will be triggered only in two situations. First, you set a particular condition for the event (**conditionally**), so each time the event is triggered, and the condition is met, then your selected action is performed.

The second situation is when you didn't put any conditions (**unconditionally**), so it will be triggered when that event happens, and there is no condition check.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.hyperdbg.org/using-hyperdbg/prerequisites.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.